The syntheses and properties of cobalt(II), nickel(II) and copper(II) complexes with some heterocyclic dithiocarbamates

New cobalt(II), Nickel(II) and copper(II) dithiocarbamato complexes of the type M(Rdtc)₂ (Rdtc = 4-phenylpiperidinedithiocarbamate and N-phenylpiperazinedithiocarbamate) have been prepared and characterized through elemental analyses, conductivity measurements, spectral (electronic and IR) studies, magnetic moment measurements at different temperatures, e.p.r. techniques and thermal analyses (TG and DTG). The dithioligands exhibit bidentate behaviour in all the complexes. The magnetic moments studies suggest that there is no significant interaction between copper ions, and the e.p.r. data provide parameters typical of sulphur coordination in planar CuS₄ chromophores.     

The preparation and crystal structure analysis of a 2:1 complex between L-lysine and copper(II) chloride

The crystal structure of bis(L-lysine)Cu(II) chloride dihydrate has been determined by X-ray analysis. The complex crystallizes in the monoclinic space group P2₁, with cell dimensions a = 5.189(1), b = 16.988(3), c = 11.482(2) Å, β = 93.57(1)°. The position of the Cu atom was found from a Patterson synthesis, the remaining atoms were located with DIRDIF. The structure was refined by least-squares to R = 0.060 and R_w = 0.065 for 2637 observed reflections. The copper(II) atom has an essentially square planar coordination with the two lysine molecules chelated via the carboxy oxygen and the α-amino nitrogen. However the two chlorine atoms form weak interactions with the metal to complete a strongly tetragonally elongated six-fold coordination. The two aliphatic chains have rather different geometries and are extended in a zig-zag mode. Extensive hydrogen bonding links the complex and the water molecules together.     

Tetrahedral 1:1 adducts of guanine with cobalt(II), copper(II) and zinc(II) chlorides

Adducts of the M(guH)Cl₂ type were prepared by refluxing 2:1 molar mixtures of guanine (guH) and MCl₂ (M = Co, Cu, Zn) in ethanol-triethyl orthoformate for 2–3 days. Characterization studies suggest that all three new complexes involve distorted tetrahedral configurations. A linear chainlike polymeric structural type with a single-bridged (-MguH-)_n backbone and two terminal chloro ligands per metal ion (MN₂Cl₂ chromophore) is proposed for these compounds, in view of their poor solubility in organic media, their stoichiometry in conjunction with their tetrahedral symmetry, and the reported crystal structures of 9-methyladenine analogs (M = Co, Zn), which are polymeric with single bridges of the adenine derivative between adjacent metal ions. Bidentate bridging guH coordinates exclusively through ring nitrogens, and is most probably N(7), N(9)-bonded. The possibility of use of exocyclic potential ligand sites of guH (CO oxygen or NH₂ nitrogen) in coordination is ruled out by the infrared evidence [1].     

The copper(II) catalyzed reaction of L-ascorbinc acid with tris(oxalato)cobaltate(III) ion in aqueous solution

The kinetics of the reaction between tris(oxalato)cobaltate(III) ion and L-ascorbic acid were studied in aqueous solution over a range of copper(II) ion concentrations, ascorbic acid concentrations, pH values and temperatures. A rate law of the type rate = k[HA^?][Cu²⁺][Co³⁺], where HA^? = ascorbate, is suggested by the experimental results. A mechanism involving a copper-ascorbate complex is proposed.     

Copper(I) and copper(II) complexes of biologically relevant tridentate ligands

The preparation of a series of tridentate ligands of formulae X(CH₂C₇H₅N₂)₂ (X = NH, S, O, S₂) is described. The ligands contain two benzimidazole moieties and one of NH, S, O, or S₂ as the donor groups. Cu(I) and Cu(II) complexes of these ligands are prepared and characterized. Spectroscopic and X-ray data imply that the geometric constraints of these ligands impose a distorted coordination geometry at copper. The implications and relevance of this chemistry to copper proteins is discussed.     

A polarimetric study of the reaction of bis(L-serinato)copper(II) with formaldehyde

Polarimetric data have shown that the base-catalyzed reaction of bis(L-serinato)copper(II) with excess formaldehyde proceeds via the initial dissociation of the proton on the nitrogen atom of the amino acid chelate. A bis(oxazolidine)copper(II) complex appears as an intermediate but this species is not detected polarimetrically at 50°C and above.     

Complexes of dibenzoyldisulphide with metal halides. Part III. Complexes of dibenzoyldisulphide with cobalt(II), nickel(II), manganese(II), copper(II), iron(III) and chromium(III) halides

Adducts (1:1) of halides of cobalt(II), nickel(II), manganese(II), copper(II), iron(III) and chromium(III) with dibenzoyldisulphide have been isolated and characterized on the basis of elemental analysis, molar conductance, magnetic susceptibility, infrared spectra, molecular weight and thermogravimetric analysis data.     

Binuclear schiff base complexes of nickel(II) or copper(II) linked by dithiols as a bridging group

Binuclear Schiff base complexes of nickel(II) or copper(II) were synthesized by bridging unsymmetrical Schiff base complexes of nickel(II) and copper(II) with 2,5-dimercapto-1,3,4-thiadiazole or 2-mercaptoethyl ether.Although the magnetic susceptibility and ESR measurements showed that copper(II)copper(II) interaction of the binuclear copper(II) complexes is very weak in the solid state, they catalyzed chemiluminescence of luminol by hydrogen peroxide in DMF solution, suggesting that small amounts of the complexes might be present in the form of the appropriate copper(II)copper(II) distance to activate hydrogen peroxide in solution.     

Crystal and molecular structure of μ-propane-1,3-diamine Di[bis(propane1,3-diamine) copper(II)]perchlorate complex

The title compound, [Cu₂(1,3-pn)₅](ClO₄)₄, crystallizes in the orthorhombic space group Pbca with Z = 8 formula units in a cell of dimensions: a = 30.88(9), b = 14.664(6), c = 15.737(6) Å. The structure was solved by the heavy-atom method and refined by least-squares calculations to R = 0.082 for 3156 counter data. It consists of discrete dinuclear [Cu₂(1,3-pn)₅]⁴⁺ cations and ClO₄⁻ anions. In the dinuclear cation two propane diamine molecules act as chelating to each copper atom in the basal plane; the fifth amine molecule in an extended form, with its nitrogen atoms located at the apices of two square-pyramides, bridges two copper atoms. Magnetic and spectroscopic data are also discussed.     

Metal—phenoxyalkanoic acid interactions. Part 14. The crystal and molecular structures of diaquabis(4-fluorophenoxyacetato)copper(II) bis(4-fluorophenoxyacetic acid)dihydrate and tetra-μ-(4-fluorophenoxyacetato-0,0′)-bis[(2-aminopyrimidine)copper(II)]

The crystal structures of two copper(II) complexes of 4-fluorophenoxyacetic acid (4-FPAH) have been determined by X-ray diffraction. [Cu(4-FPA)₂(H₂O)₂]·2(4-FPAH)·2H₂O (1) is triclinic, space group P1 with Z = 1 in a cell of dimensions a = 14.808(2), b = 9.832(2), c = 6.847(2) Å, α = 87.77(2), β = 98.41(2), γ = 112.33(2)° and was refined to a residual of 0.038 for 1697 ‘observed’ reflections. The coordination sphere in this complex is tetragonally distorted octahedral comprising two waters [CuO, 1.940(3) Å], two unidentate carboxylate oxygens [CuO, 1.942(2) Å] and two ether oxygens [CuO, 2.471(2) Å]. Two adducted [4-FPAH] acid molecules are linked to the un-coordinated oxygens of the acid ligands by hydrogen bonds [2.547(4) Å]. [Cu₂(4-FPA)₄(2-aminopyrimidine)₂] (2) is triclinic, space group P1 with Z = 1 in a cell of dimensions a = 12.688(2), b = 11.422(2), c = 7.951(1) Å, α = 78.74(1), β = 107.51(1), γ = 75.78(1)°, and was refined to a residual of 0.042 for 2683 ‘observed’ reflections. (2) is a centrosymmetric tetracarboxylate bridged dimer with four similar CuO (equatorial) distances [1.967–1.987 Å; 1.977(3) Å mean] and the axial position occupied by the hetero nitrogen of the 2-aminopyrimidine ligand [CuN, 2.176(3) Å]. The Cu---Cu separation is 2.710(1) Å. Crystal data are also presented which confirm the isostructurality of complex (2) with [Cu₂(phenoxyacetate)₄(2-aminopyrimidine)₂], the Co^II, Mg^II and Mn^II4-fluorophenoxyacetate complexes with their phenoxyacetic and 4-chlorophenoxyacetic acid analogues, and of Cd^II4-fluorophenoxyacetate with Cd^II and Zn^II phenoxyacetates.     

Antitumor activity and metal complexes of the first transition series. Trans-bis(salicylaldoximato)copper(II) and related copper(II) complexes,a novel group of potential antitumor agents

The antitumor activity of forty nine different metal complexes of the first transition series against mouse leukemia L 1210 cells and of two of the complexes against Ehrlich ascites carcinoma have been tested in vitro by the method described in this paper. Eight complexes showed a 50% inhibition of tumor cell division at concentration level 5–6 μg/ml of the complex for the former and two most effective complexes also for the latter. The trans-bis-(salicylaldoximato)copper(II) and trans-bis(resorcylaldoximato)copper(II) complexes were found to possess the highest antitumor activity.     

Manganese(II), iron(II) and nickel(II) chloride complexes with monodeprotonated anionic guanine

Upon refluxing 2:1 mixtures of guanine (guH) and MnCl₂, FeCl₂ or NiCl₂ in a 7:3 (v/v) mixture of ethanol and triethyl orthoformate for 1–2 weeks, partial substitution of gu^? for Cl^? groups occurs, and solid complexes of the M(gu)Cl·2ROH (R = C₂H₅ for M = Mn; R = H for M = Fe, Ni) type are obtained. The new complexes are pentacoordinated and appear to be linear chainlike polymeric species, involving a single-bridged

_n backbone. Coordination number five is attained by the presence of one terminal chloro and two terminal ROH ligands per metal ion. Most probable binding sites of bidentate bridging gu^? are the N(7) and N(9) imidazole ring nitrogens. IR evidence rules out the possibility of coordination of gu^? through any of the exocyclic potential ligand sites (O(6) oxygen or N(2) nitrogen) [1].     

Synthesis and characterization of a series of new mixed ligand complexes of manganese(III), iron(III), nickel(II), copper(II) and zinc(II) with schiff bases of N,N-diethylamino-dithiocarbamate as ligands

Twenty new bioactive complexes of Mn(III), Fe(III), Ni(II), Cu(II) and Zn(II) have been prepared containing Schiff bases of N,N-diethylaminodithio- carbamate as ligands. These complexes have been characterized by elemental analyses, IR and UV-Vis spectroscopy as well as by magnetic susceptibility measurements. The spectra of the complexes suggest that the ligands are coordinated to the metal ions via the sulfur atoms of the dithiocarbamato group.     

Binuclear copper(II) complexes of some potentially sexadentate phthalazine hydrazone ligands

Binuclear copper(II) complexes of three potentially sexadentate phthalazine hydrazone ligands, obtained by reacting 1,4-dihydrazinophthalazine with an appropriate aldehyde, are reported, in which variable terminal donor substituents include the phenol (DPSI), N-methyl imidazole (DPIM) and pyridine (PHP) groups. For the phenol substituted ligand (DPSI) the phenol residues are sufficiently acidic that in most cases this ligand behaves as a dianion. Hydroxy bridged structures are proposed in almost all cases based on analytical, infrared and magnetic data. Reduced magnetic moments are observed for all compounds indicating anti-ferromagnetically coupled copper(II) centres and in six cases magnetic moments of < 0.5 BM are observed. The copper(II) centres appear to have distorted square planar stereochemistries in the systems which involve two metals bound to each ligand. In one case involving the copper chloride complex of DPIM a polynuclear system is proposed involving three metals per ligand.     

Five-coordinated metal complexes of bis(2-hydroxy-1-naphthylideneimine-3-propyl)amine and their reactivity towards dioxygen. Part I. An electrochemical investigation on manganese(II), iron(II), cobalt(II), nickel(II) and copper(II) complexes

The electrochemical behaviour in aprotic solvent of the complexes {M[bis-(2-hydroxy-l-naphthylideneimine-3-propyl)amine]}, where M = Mn(II), Co(II), Fe(II), Ni(II) and Cu(II) is reported. The complexes were prepared and characterized by elemental analysis, infrared and visible spectroscopy and magnetic susceptibility measurements. In addition the reactivity towards dioxygen of the Mn(II), Fe(II) and Co(II) derivatives was investigated, mainly by cyclic voltammetry and gas-volumetric uptake measurements. The results indicate that the Co(II) complexes are able to add dioxygen reversibly, while Mn(II) and Fe(II) compounds undergo an irreversible oxygenation process. The pathway of the dioxygenation processes is tentatively interpreted on the basis of the electrochemical responses. The results confirm that the location of the oxidation potential allows one to predict whether a compound is able to react with dioxygen, but it is not sufficient to predict whether the dioxygenation reaction proceeds reversibly.     

Crystal and molecular structure of tris(propane-1,3-diamine)nickel(II) dinitrate complex

The title compound, [Ni(1,3-pn)₃](NO₃)₂, crystallizes in the orthorhombic space group Pbca with eight formula units in a cell of dimensions a = 17.146(8), b = 14.364(5) and c = 15.054(7). The structure was solved by the heavy-atom method and refined by least-squares calculations to R = 0.053 for 1439 counter data. It consists of discrete, slightly distorted octahedral [Ni(1,3-pn)₃]²⁺ cations and NO₃^? anions. One of the three six-membered chelate rings show a pronounced flattening unusual chair conformation. Magnetic and spectroscopic data agree to a lower stability of six-membered chelate rings, compared to five-membered chelate ones.     

Imidazole-containing ternary complexes of N-benzyloxycarbonyl-aminoacids. Crystal and molecular structure of bis(N-benzyloxycarbonyl-alaninato)bis-(N-methylimidazole)copper(II) ethanol solvate

Mixed ligand complexes of the type Cu(Z-aminoacidato)₂(B₂) (Z = benzyloxycarbonyl group, Z-aminoacidate = Z-glycinate (Zgly), Z-alaninate (Zala); Z-valinate (Zval), Z-leucinate (Zleu) ion, B = imidazole (Im), N-methylimidazole (MeIm)) were synthesized and characterized by means of electronic, infrared and EPR spectroscopies. For one of them, bis(Z-alaninato)bis(N-methylimidazole)copper(II) ethanol solvate, the crystal and molecular structure was also determined by the single crystal X-ray diffraction method. The complex crystallizes in the monoclinic space group P2₁/c, with cell dimensions a = 11.1119(6), b = 18.8398(7), c = 8.9652(5) Å, β = 105.380(2)° and Z = 2. The structure was solved by conventional Patterson and Fourier methods and refined by full-matrix least-squares to an R value of 0.045. The complex has square-planar coordination via two centrosymmetric carboxylic oxygens and two N-methylimidazole nitrogens. The second carboxylate oxygen is 2.731(5) Å from the copper atom in an ‘out of plane’ position. Packing is mainly determined by hydrogen bondings between amide nitrogen and amide carboxyl oxygen. Electronic, infrared and EPR spectra are consistent with this type of coordination geometry for anhydrous complexes, while for hydrate complexes are suggestive of tetragonal bipyramidal geometry.